PALLETIZER

The irvention relates to an apparatus for stacking objects. Sαch stacking apparatuses are used for instance for stacking products on a carrier, such as a pallet or a roller container.

When stacking products of different dimensions or shapes, the stacking pattern should be optimised ir. such a way as will enable as many products as possible to be stacked m a stable manner.

NI 1025826 discloses a palletising apparatus which is used in particular for products having different dimensions. After a stacking layer has been formed, the layer is moved with the aid of a conveyor belt to a stacking area. During that movα ng the stacking pattern of the formed layer, is maintained using means provided especially for the purpose.

The object of the present invention is to provide an apparatus which enables efficient and stable stacking at high speed of products of various dimensions and shapes on a carrier,, such as a pallet or a roller container.

The object of the invention is attained with an apparatus for stacking objects on a carrier wherein the apparatus is provided with a forming platrorm, a loading platform on which a transport carrier to be loaded can be placed, and a gripper which is movable between the forming platforn and the loading platform, wherein the gripper comprises a support frame which is provided with at least one row of parallel forks, which

forks comprise an upright to which a beam is attached at a distance beneath the support frame, wherein the beams can be moved backward and forward in tneir longitudinal direction, wherein each fork is individually adjustable vis-a-vis the 5 support frame. The support frame can for instance oe provided on two opposing sides with forks comprising an upright to which a longitudinally movable beam is attached at a distance beneath the support frame, wherein the beams can be moved backward and forward longitudinally in the direction of the opposing row of 10 forks, wherein each fork is individually adjustable vis-a-vis the support frame.

In order to obtain a high flexibility, each upright can be provided with an individual drive unit for moving up and down.

_5 As a result of this, the various beams can be kept at different levels. When a layer to be stacked is placed on top of a lower, already stacked layer of products of different heights, then the products, which are to be placed iowe: can be maintained in a .ower position, so that the height of fall from the beam to

10 the final position in the stack can be kept as small as possible for every product.

Each bean can also be provided with an individual drive unit for moving backward and forward in longitudinal direction, Th:. s '5 makes it possible to retract a section oi the beams earlier, or to keep a section of the beams retracted while moving the products to be stacked.

If both the beams and the uprights can be moved individually in 0 a horizontal and a vertical direction, respectively, it becomes possible to stack a wide range of diverse products, wnich may for instance be of different dimensions, type and/or weight, on

one and the same pallet and even xn rhe same stacking layers. Also, compared with the stacking systems known so far, rhis offers more possible ways of positioning prodαcts on a carrier. When products of different heights are stacked, the top side of

0 a stacked layer will form an uneven plane onto which a next layer of produces has to be stacked. The products of the nexi layer to be stacked then have to be put down at different levels. Because of the mutually independent vertical adjustability of the forks, those products, despite tne

0 different levels at which they eventually end up, ran still be stacked m one go as one layer. This can take place for instance in two steps. On the forming platform the products to be stacked are arranged at the same level. Next, they are lifted up by the gripper, which moves the layer of products to

5 the loading platform. During this movement one or more of the forks can be vertically adjusted :n such a way that tne products being carried end up at the same relative height as in the stacking layer which is ultimately to be formed. Next, the gripper places the supplied layer on the layer or layers iO already stacked. The vertical adjustment of the forks in that case thus rakes place on the way fron the forming platform to the loading platform.

The vertical adjustment rate of the uprights can be for 1S instance up to 1 m/sec, for instance up to 0.8 m/sec. The horizontal adjustment rate oi the beams can be higher, for instance up to 2 n/sec, for instance 1.7 m/sec.

Depending on their calculated position in the layer to be !0 stacked, the products to be stacked can be carried by the ends of two opposing beams. This will generally be the case when a product is to be positioned at the centre of a layer to be

stacked. By not placing the opposing teams end to end, the ends oi the beams ran be placed side by side over a particular distance. This can result in as many products as possible being put in place m a single remove, thαs saving time.

The gπpper can for instance be capable of rotation about a vertical axis, for instance be capable of rotation through an angle of 180 degrees or 360 degrees or more. As a result of th's, the ready carrier on wnirb the stack to be formed is placed can be approached from several sides. This makes even more complicated stackings possible.

The gripper can for instance be disconnectablo. This makes ii possible for the qripper Lo be replaced by a qripper with a greater capacity when this is called for.

The gripper can be conriecLed to a multi-axial removal apparatus, such as for instance a flexible arm robot.

The stacking apparatus according to the invention can be modular, in which case the number or the capacity of the forming platforms, loading platforms, and grippers can be varied according to need. Tf so desired, the lay-out of the stacking apparatus nay also be provided with one or more buffer zones.

The forming platform can be provided with parallel grooves of a width which corresponds easily with the width of tne beams . As a result of this, the beams can be slid underneath the products to be stacked in order to then be lifted up when the gripper is moved upward .

The beam can be provided with a strap running longitudinally around the beam across the beam's top side and underside, which strap is connected to the upright by two ends. The products to be moved in that case rest on the strap around the bean. When 5 the bean is retracted, the strap stays in place, but is gradually rolled out from under the product. As a result of this, the product docs not have to be slid off the beam. This enables more precise positioning of the product when it is stacked, In order to guide the strap properly around the beair,

10 the beam can be provided on the two crosscut sides with a roller guide along which the strap is guided. In order to optimise the grip on the product, the strap car. be made or a non- slipping material, such as rubber nitrile (NBR) elastomer, optionally on a core of a carrier strap material such as a

15 polyamide.

If so desired, the gripper may be provided with a number of vacuum heads which car. xove up and down. With these the products can be positioned more precisely still during the 20 stacking and the product can be supported during the fall from the beam to the final position in the stack.

The apparatus according to the invention can be combined with a pro-sorting unit and/or a preferably automated order picking 25 system. This makes it possible to calculate the optimal stacking structure for a particular order already in advance and to have the products supplied in the correct sequence.

With the aid of one, two or more positioning arms, the supplied 30 products can be put or slid, for instance from a supply strap, onto the forming table in the correct position and in the proper place and, optionally, be turned.

After a layer has been stacked, the layer can be compressed in order to achieve the desired compacting. The compressing can take place on all four sides of the layer. In order to increase the stability of the stack, a strap made for instance of plastic can be wound around one or more of the stacked layers lor instance around every second or third layer. Alternatively, after the stacking tne complete stack forired on the carrier can be wrapped, for instance with a foil, before the carrier with the stack is dispatched.

The stacking apparatus according to the invention makes it possible for products of very diverse dimensions to be stacked. Small products, say of 10 cm high or wide, as well as large products, say as J arge as the pallet itself, can be stacked. The stacking o: flexible products, such as clothing, can also oe performed in an efficient manner. This can be done for instance by positioning products with solid packaging around the periphery of the carrier, m which case the flexible products can then be positioned in the space enclosed by the solid packages.

The invention will be further elucidated wit.i reference to the drawing, In the drawing:

Figure 1 shows a stacking apparatus according to the invention; Figure 2 shows the positioning arm of the stacking apparatus according to Figure 1;

Figure 3 shows the forming table of the stacking apparatus according to Figure 1;

Figure 4 shows tne gripper head of tne stacking apparatus according to Figure 1;

Figure 5 shows the gripper head of Figure 4 during the carrying of a stacked layer;

Figure 6 shows a fork of the gripper head according to Figure 4;

5 Figure 7 shows in detail an end of a fork according to Figure 6;

Figure 8 shows in schematic elevation the gripper head of the apparatus according to Figure 1 during stacking on a pallet; Figure 9 shows in perspective view the gripper head of Figure 4 10 during stacking on a pallet;

Figure 10 shows the compacting station of the apparatus of Figure 1;

Figure 11. shows a gripper head according to the invention which is particularly suitable for stacking on rol ler containers.

15 Figure 1 shows an apparatus 1 for stacking products 2 on a roller container 3 or a pallet 4 , The products 2 can have different shapes and dimensions. The apparatus 1 comprises a supply belt 5 for the supply of the products to be stacked 2. The products 2 are supplied with the aid of a pre-sorting unit

20 by way of a supply pipe 6 in a sequence which makes it possible to achieve optirral stable stacking. The. supply belt 5 is disposed in a frame 7, in which a positioning arm 8, which is shown m greater detail in Figure 2, is suspended. The positioning arm 8 can be moved in a direction parallel with the

25 longitudinal direction X of the supply belt 5 as well as in a direction Y perpendicular, thereto and can in addition be rotated in a direction α about an axis perpendicular to the supply belt 5. As a result of this, the positioning arm 8 is capable of picking up products 2 supplied from the supply pipe

30 6 and of moving and, if necessary, turning them. The thus positioned products 2 are conveyed onwards by the supply belt 5

and moved to a forming rable 9, where they are put ir. the desired position by a second positioning arm 8A, The products 2 have been positioned such by the positioning arm 8 as to form a layer to be stacked on the forming table 9,

Figure 3 shows the form: ng table 9 :.n detail. AL the top side, the forming lable 9 is provided with a number of parallel evenly spaced ribs 10, which bound continuous grooves 11 of equaJ width. AL the underside the forming table 9 is provided with guide profiles 12 having a U-shaped cross-section. The guide profiles 1? are parallel with the grooves 11.

As shown in Figure 1, the forming table 9 is placed on a support frame 13 with two guide rails 14 extenoing in the longitudinal direction of the frame, which guide rails have been mated with the guide profiles 12 on the underside of the forming table 9. As a result of this, the table 9 can be moved forward and backward between a forming position where the forming Lable 9 connects to the supply oelt 5 - as shown m Figure 1 - and a discharge position at the other end of the supporL fr arae 13.

The apparaLus 1 additionally comprises a loading platform, or stacking area 20 and a gripper head 30. The gripper head 30 can be moved by way of a guide frame 31 between a position above the stacking area 20 and a position above the forming table 9 when this is situated in the discharge posit ⁱ on at the end of the support frame 13. In both uttermost positions the gripper head 30 can be moved up and down. The gripper head 30 is shown in detail in Figure A. Figure b shows the sane grjpper head 30 in the course of carrying a formed layer of products 2.. The gripper head 30 comprises a rectangular support lrame 32

suspended from the end of a vertical bearing girder 33. The support frane 32 is provided on two opposing sides with a row of forks 34. Figure 6 shows an individual fork 34. Each fork 34 comprises a vertical profile 35, into which a telescopically 5. extendable upright ?6 .is .incorporated which can be moved up and down vis-a-vis the vertical profile 35 with the aid of a drive unit 37 and a spindle gear (not shown) . On the undorsioe of each extendable αpπght 36 a shoe 38 is attached, into which a bean 39 is slidably incorporated. All beams 39 are parallel

10 with each other and can be moved backward and forward longitudinally vis-a-vis the shoe 38 by way of a toothed gear rack (not shown) driven by a motor 40. All round each beam 39 there are two parallel non-slippmg straps 41. The non-slipping straps 41 go across the top side and the underside of the beam

15 39 by way of the crosscut sides of the beam 39. Fach non- slipping strap 41 has two ends 42, 43, which are attached on either side of the shoe 38.

As is shown in detail by Figure 7, the beam 39 is provided on 20 either end with a bend pulley 44, the axis of which :s at right angles to the .longitudinal direction of the beam 39. The non- slipping straps 41 run round about the bend pulley 44. When the beam 39 is moved backward and forward, the non-slipping straps 41 remain in place. In this way it is brought about that any 25 products 2 which are positioned on the beam ?9 do not have to be slid off the beam 39 when the beam 39 is retracted. On retracting the beam 39 the straps 41 are rol led out f ron under the product 2 and the product 2 regains in the same place.

30 in the embodiment of Figure 7 the non-slipping strap 41 consists of two parallel straps. If so desired, however, the

strap 41 may consist: o± a single strap, or the beam 39 may be divided into two parallel, individually movable beams.

The upπghrs 36 and the beams 39 are individually movable. This 5 enables a segmented driving of the gripper head 30,

When a layer of products 2 has been formed or. the foriring table 9, the gripper head 30 can be moved to the forming table 9, in which process all beans 39 are as fully retracted as possible,

LO 'Ihe gripper head 30 can then be positioned over the formed layer. When the beams 39 are ir. the same straight .line as the grooves 11 in the forming table 9, the beams 39 can be moved cowards each other again by way of rhe grooves 11, into which they can De incorporated with ample clearance. The gripper head

L5 30 can then lift the formed layer, after which the gripper head 30 is moved by way of the guide frame 31 to the stacking area 20, This situation is depicted schematically in Figure 8. After tnat, rhe foimed layer of products 2 is lowered jnti! it comes to rest on a pallet 50 standing in readiness, optionally on

.0 lower layers of products 2 which have been stacked on the pallet 50 earlier. The non-sl ippmg strap 41 does not move with the beams 39 as they are retracted, so that the products 2 which are on the bean 39 do not have to be slid off the beam 39. The products 2 remain in place while the non-slipping

!5 straps 41 arc rolled out from under the products by the beam 39, The products 2 are thus posited on the underlying layer.

The uprights 36 can be controlled independently. As a result of this, the beams 39 may, if so desired, be kept at different !G levels, so rhat some products 2 can be kept lower than other products 2, as is shown for instance in Figure 8. If one or more layers of produces 2 have already been stacked on the

pallet 50, then the product, 2 which is stacked υntυ a less high produce 2 can be kept lower rhan products 2 which are stacked on.ro a higher product 2. Thus the height of fall is kept as low as possible for all products 2.

Ti so desired, means may be used to support the products during the stacking , These nay for instance be vacuum heads 51, as shown in Figure 8.

Alternatively, the beams 39 can be retracted independently. If the pαlle: 50 already holds a previously stacked layer of products 2 of unequal height, then the beams 39 on which there are products 2 which άxe placed on high products 2 can oe retracted first. After that, zhe gripper head 30 can be lowered and a next product 2 can be posited on a product 2 on a slightly lower level. Alternatively, a beam 39 can be retracted m stages, in which case the product 2 is first placed on the end of the beam 39, after which, if necessary, the beam 39 can be lowered in order to then be retracted farther for a next product 1 to be put in place. Alternatively, the gripper head 30 can be used to move just part of a layer. The beams 39 on which there are no products 2 then in that case can be kept in the retracted position, as is shown in Figure 9. Where the beams 39 have been retracted, the gripper head 30 can be lowered over αpriαht products 2 of a previously stacked layer Ir- order to put new products 2 to be stacked in place on the remainder of the previously stacked layer.

The stacking area 20 consists of a roller conveyor 60. Between the rollers 61 oi the roller conveyor 60 there are three partitions 62 which project above the roller conveyor 60 during the stacking, as is shown in greater aetail m Figure 10. On

the partitions 62 is placed the pallet 4 onto which the products 2 are stacked. Next to the partitions 62 a compacting station 63 is placed. The compacting station 63 comprises an upright 64 on which a supporting arir adjustable in height is mounted. On the supporting arm 65 « horizontal frame work 66 is nounted, which is dimensioned and positioned such that it can be J owered over a stack of products 2 on a pallet 4 on the partitions 62. On each of the four inner sides oi the frame work 66 there is a pressure member 67. By moving the pressure menoers 67 inward, the products 2 in a stacked layer are moved toward each other and the stack is compacted until the desired degree of compacting is obtained, in order to increase the stability of the stack, a plastic clamping strap can be wound around every second or third layer. After a whole stack of products 2 has been stacked and compacted, the partitions 62 are lowered jr.til the pallet -1 stands on the rollers 61 of the roller conveyor 60, while the frame work 66 is raised. The pallet 4 with the stack of products 2 can then be removed by way of the roller conveyor 60.

After the stacking the complete stack on the carrier is wrapped in a foil in a separate station, before the carrier with the stack is dispatched.

Figαre 11 shows a gripper head 60 according to the invention which is especially equipped for use with roller containers 70. The gripper head 60 to this end comprises a support frame 61, which is provided with two parallel rectangular grooves 62 between two plate-shapeo crossbeams 63, through which the raised sides /1 of the roller containers 70 can be slid. The crossbeams 63 are slightly closer together at the top side than at the underside, enabling the gripper heaα 60 to oe lowered

more easily over the sides 71 of the roller container 70. The beams 39 of the outermost forks 34 .remain in the refracted position to keep them at a distance from the sides 71 of the roller container 70, The supporting head 60 can thus be lowered over the sides 71 in order to put a layer to be stacked on the bottom 72 of the roller container 70, or on a layer previously put in place.